Trail Difficulty Ratings

On Wed, 09 Mar 2005 15:45:43 GMT, uglymoney
wrote:

On Wed, 09 Mar 2005 10:39:38 -0500, Walt
wrote:

What's an HOA? Hooters of America?

I went to a Hooters last week in Midvale. Terrible as usual. God I
love that place!


Horvath sighting?
http://cameltoe.bolt.com/images/HooterKen.jpg
(Don't click that link. Seriously. Don't do it.)

bw

bdubya wrote:
On Wed, 09 Mar 2005 15:45:43 GMT, uglymoney
wrote:


On Wed, 09 Mar 2005 10:39:38 -0500, Walt
wrote:


What's an HOA? Hooters of America?

I went to a Hooters last week in Midvale. Terrible as usual. God I
love that place!



Horvath sighting?
http://cameltoe.bolt.com/images/HooterKen.jpg
(Don't click that link. Seriously. Don't do it.)

bw

Well I went ahead and clicked it...
BAAAARRRRRRRFFFFFFFF, how could you post anything so FUGLY?

Stephen B. wrote:

Ok I finally got around to making examples of a fictitious mountain. I drew
these up on AutoCAD. Remember I am not an artist, so I have ignored the
trees and other details that do give help in depicting slopes. First check
out my version of a traditional trail map with all trails in blue.
http://www.users.cloud9.net/~romania/traditional.jpg

Then look at that mountain as drawn with what I proposed for new trail maps
http://www.users.cloud9.net/~romania/redesigned.jpg

See the arcs of the contour lines in green?

or is this the mountain http://www.users.cloud9.net/~romania/redesigned2.jpg

All three sets of trails should be identical on your screen, but don't the
contour lines tell you a different story between about the slopes of the two
redesigned maps?

Ah, yeah, okay. I like it. The only problem I see is that, while it
gives good and clear information in its current form, if you add in all
the stuff that people argue are necessary or desirable on a trail map --
particularly the "artist's rendering" style that shows fuzzy li'l trees
and white slopes and whatnot -- that'll change in a hurry.

--
Mary Malmros
Some days you're the windshield, other days you're the bug.

"Mary Malmros" wrote
Ah, yeah, okay. I like it. The only problem I see is that, while it
gives good and clear information in its current form, if you add in all
the stuff that people argue are necessary or desirable on a trail map --
particularly the "artist's rendering" style that shows fuzzy li'l trees
and white slopes and whatnot -- that'll change in a hurry.

That is why I didn't argue with Walt about it cluttering, but as a light
"highlight" I *think* it would work.

--
Stephen B.

Stephen B. wrote:

"Mary Malmros" wrote

Ah, yeah, okay. I like it. The only problem I see is that, while it
gives good and clear information in its current form, if you add in all
the stuff that people argue are necessary or desirable on a trail map --
particularly the "artist's rendering" style that shows fuzzy li'l trees
and white slopes and whatnot -- that'll change in a hurry.


That is why I didn't argue with Walt about it cluttering, but as a light
"highlight" I *think* it would work.

Yeah, or maybe we could get away from the painting-of-the-mountain style
of trail map, something a little more minimalist, like the way a topo
represents open areas and wooded areas or some such. But when you throw
in the lifts and all the cute logos for the eateries and such, well...I
dunno. But I like what you've done with it.

--
Mary Malmros
Some days you're the windshield, other days you're the bug.

Sources close to the investigation reveal that, on Tue, 08 Mar 2005
20:53:53 -0500, Mary Malmros wrote:

Bill Griffiths wrote:
Sources close to the investigation reveal that, on Tue, 08 Mar 2005

Stated in the text you snipped: "A rating system has to say things
like: areas A and B are roughly equal in difficulty, while area C is a
step down, and area D ... etc."

I think the question is, how useful is a simple rating of the overall
difficulty of an area? It's like the value of a mean: the average of
anything may not tell you much about what's being averaged, depending on
how much deviation from the mean there is. If I tell you that the
average height of a group of ten people is five feet six, what do you
really know? All ten could be five feet six...or half of them could be
four feet tall and half of them seven feet tall. The average doesn't
tell you what's typical. So I guess I'm looking for more of an idea of
how you'd express an area's rating, since obviously you wouldn't be
using anything so simple.

Your height analogy is good, but let me change it to ages. Take two
groups of people of varying ages, dressed in green, blue, or black
depending on whether they are young, in between, or old. For a
single-number rating, I would use the average age of the people in
black (though a good case could be made for the age of the oldest).
With two numbers, I would add the age of the oldest person.

The age/height analogies fail on one point: while ages and heights can
be arbitrarily concentrated (everyone 5'6"), just about every ski area
has a range of trails starting with the bunny slope. Since we know
that the range of difficulties (ages) starts with the bunny slope
(newborn), a single number rating conveys more information than an
average normally does.

Allow me to take your second example and make it germane. Assume that
LL and Local Molehill had approximately the same rating. That would
mean that the consensus of the skiers submitting ratings was that the
blacks at LL were roughly as difficult as those at LM. Thus someone
who enjoyed the blacks at LM would enjoy them at LL, and vice versa.
(An unlikely assessment, but it's not my example.)

What do you do in the case where the blacks are equivalent, but the
blues aren't?

Is this common? If so, you would need an additional number for blues.
If the relative difficulty of blues and blacks were correlated, you
would only need one number.

As for being unworkable, the system is a pretty straightforward
extension of asking people's opinions. Whether it is worthwhile to
replace individual assessments with a system is another matter -- but
my point was only that it would not be hard to develop a system.

I think it would be a bit harder than you think, with some possibly
Escher-esque contradictions -- Person 1 says area A is harder than area
B, person 2 says area B is harder than area C, person 3 says area C is
harder than area A, etc. I'm not sure how you would resolve these, how
much data would be enough to judge that you have a consensus rating, or
what you'd do about discarding outliers.

Escher-esque contradictions or cycles could be either small-scale or
large-scale. Small-scale cycles reflect small variations in the
assessment of areas that are roughly comparable; these cycles are no
problem. Large-scale cycles among greatly disparate areas would mean
that the whole concept of difficulty was nonsense (just as there is no
"best choice" in rock/paper/scissors) -- but if this were the case, it
would surely show up in ordinary conversation.

Another pitfall is that rankings may not be comparable across regions.

As for the specifics of how much data, outliers, etc. -- these are
important but routine questions. While you would have to answer them
in order to actually construct a ranking, there is no reason to assume
that you couldn't. This isn't an actual answer to your question, but
a real answer would involve a fair amount of boring grunt work.

Oh, and by consensus I mean something along the lines of mean +/-
confidence interval.

--
Bill Griffiths
"The fool hath said in his heart, there is no such thing as justice." Hobbes

Mary Malmros wrote:

I don't think you need to do an exhaustive analysis to say that there
are more ski trails than whitewater rivers. The whole state of Vermont
doesn't have 200 rivers that have been rated, or river sections.
[killington examples snipped]

This is an unfair comparison. One river can stretch for a considerable
distance. Lets compare miles of ski trails with miles of river.
Arizona is considered a desert state yet has quite a few rivers that
people run, the colorado, salt and black being the most popular. I
wouldn't try to say theres only 3 rivers in Arizona but 4 ski areas with
dozens of ski trails. Those rivers combined are well over 100 miles
long of runable water.

miles wrote:

Mary Malmros wrote:

I don't think you need to do an exhaustive analysis to say that there
are more ski trails than whitewater rivers. The whole state of
Vermont doesn't have 200 rivers that have been rated, or river sections.
[killington examples snipped]


This is an unfair comparison.

"Unfair"? I don't see what fairness has to do with anything; this isn't
a matter of social justice, it's about rating rivers vs. rating trails.

One river can stretch for a considerable
distance. Lets compare miles of ski trails with miles of river. Arizona
is considered a desert state yet has quite a few rivers that people run,
the colorado, salt and black being the most popular. I wouldn't try to
say theres only 3 rivers in Arizona but 4 ski areas with dozens of ski
trails. Those rivers combined are well over 100 miles long of runable
water.

That's all true, but the point under discussion was the river rating
system and why something similar could/couldn't be done for ski trails.
You don't rate every mile of runnable water; you rate rivers or river
sections, or note rapids as they're an exception to the general class of
the river. You might have a hundred miles of runnable river in AZ, but
I doubt you have a hundred different class ratings.

--
Mary Malmros
Some days you're the windshield, other days you're the bug.